I don't understand why anyone is using gmail as their main mail account. I really don't like the interface and using it with 3rd party apps like thunderbird, K9 mail or any other client just sucks
How? I've never had any issues using gmail with Thunderbird on desktop or FairEmail on Android. By comparison, Proton mail I could get working in Thunderbird with Proton's mail bridge, but on Android I'd be stuck using their app.
Until the entire email protocol changes there are basically just no truly good options.
I just use posteo and that works with every client from everywhere. I was not saying "gmail sucks proton mail good". I don't use proton mail. But using gmail with their weird Folder structure I get notifications about new mail basically 3 times because it is in 3 folders at the same time... It works with their interface (and probably app) but with nothing else...